Question

An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved.

Answer 1

Sodium when burnt in air, burns with a golden flame so, element A is sodium. Since element B has an atomic number of 17 so, it is chlorine. When sodium reacts with chlorine it forms sodium chloride.

`2"Na" + "Cl"_2 -> 2"NaCl"`

When an aqueous solution of sodium chloride is electrolysed it liberates hydrogen and chlorine gas and another aqueous product sodium hydroxide so, the compound D is sodium hydroxide.

`2"NaCl" + 2"H"_2"O" -> 2"NaOH" + "H"_2 + "Cl"_2`